The present invention relates to a rotor of an electrical machine having a plurality of partial laminated cores which are each at a defined distance from one another in the axial direction, such that radial cooling slots are formed. The present invention furthermore relates to a method for production of a rotor such as this. These rotors may be used in a motor, or else in particular in a generator.
High-speed wind power generators are nowadays, without exception, slipring-rotor machines with radial cooling slots. One such machine is illustrated in the form of a partially sectioned view in FIG. 1. The generator 1 has a rotor 2 with an axially segmented laminated core. Individual partial laminated cores 3 are joined together on a shaft 4 to form the overall laminated core. The individual partial laminated cores 3 are separated from one another in a defined manner, thus resulting in radially formed cooling slots 5.
At the end opposite the drive end, the shaft 4 is fitted with a slipring unit 6, in order to tap off the generated current. The associated sliprings 7 and the three double brushes 8 can be seen in FIG. 1.
For cooling, the stator 9 of the generator 1 is also provided with radial cooling slots. The heat is dissipated from the generator 1 by means of an air-air heat exchanger 10. This blows external cooling air 11 in the axial direction of the generator 1 through cooling rods 12 in the interior of the heat exchanger 10. The cooling air in the interior of the cooling rods 12 absorbs the heat of the generator 1 and transports it at the other end out of the heat exchanger 10, as is shown by heated exhaust air 13 in FIG. 1.
Together with the interior of the air-air heat exchanger 10, the interior of the generator 1 is used for a closed cooling circuit 14. Corresponding to this closed cooling circuit, cool air is blown axially into the laminated rotor core. The cooling air flows through the radial cooling slots in the rotor 2 and in the stator 9, and is heated in the process. The heated air flows into the heat exchanger 10, and is cooled down on the cooling tubes 12. It is then passed to the rotor 2 again. The closed cooling circuit makes it possible to avoid the generator from being contaminated, for example, by dust, salt water etc.
Furthermore, PM machines (permanent-magnet machines) with internal magnets are also known. The permanent magnets are in this case located underneath the envelope surface of the laminated rotor core, in pockets provided specifically for this purpose. The permanent magnets can be pushed axially into the respective pockets during assembly. Effective cooling of the rotor in these PM machines is problematic.